Implantable carrier member having a non-communicative lumen

ABSTRACT

A non-communicative lumen for electrode assemblies of medical implants, in particular prosthetic hearing implants, is provided by the present invention. The non-communicative lumen prevents the lumen within the cochlea from being able to transport fluids, cells, bacteria, tissue, etc., with the lumen outside the cochlea, and vise versa through the incision or cochleostomy. The lumen may have a cavity or slit that receives a stylet during insertion of the electrode assembly.

BACKGROUND

1. Field of the Invention

The present invention relates generally to electrode assemblies and,more particularly, to a non-communicative lumen for an electrodeassembly.

2. Related Art

There are a variety of medical implants which deliver electricalstimulation to a patient or recipient (“recipient” herein) for a varietyof therapeutic benefits. For example, the hair cells of the cochlea of anormal healthy ear convert acoustic signals into nerve impulses. Peoplewho are profoundly deaf due to the absence or destruction of cochleahair cells are unable to derive suitable benefit from conventionalhearing aid systems. Prosthetic hearing implant systems have beendeveloped to provide such persons with the ability to perceive sound.Prosthetic hearing implant systems bypass the hair cells in the cochleato directly deliver electrical stimulation to auditory nerve fibers,thereby allowing the brain to perceive a hearing sensation resemblingthe natural hearing sensation.

The electrodes implemented in stimulating medical implants varyaccording to the device and tissue which is to be stimulated. Forexample, the cochlea is tonotopically mapped and partitioned intoregions, with each region being responsive to stimulus signals in aparticular frequency range. To accommodate this property of the cochlea,prosthetic hearing implant systems typically include an array ofelectrodes each constructed and arranged to deliver an appropriatestimulating signal to a particular region of the cochlea.

To achieve an optimal electrode position close to the inside wall of thecochlea, the electrode assembly should assume this desired position uponor immediately following implantation into the cochlea. It is alsodesirable that the electrode assembly be shaped such that the insertionprocess causes minimal trauma to the sensitive structures of thecochlea. Usually the electrode assembly is held in a straightconfiguration at least during the initial stages of the insertionprocedure, conforming to the natural shape of the cochlear onceimplantation is complete.

SUMMARY

In one aspect of the present invention, an electrode assembly forimplantation in a recipient's cochlear via a cochleostomy is disclosed.The electrode assembly comprises an electrode array and an elongatecarrier member having a lumen extending longitudinally through at leasta portion thereof, and having a distal end on which said electrode arrayis disposed. The elongate carrier member comprises a distalintra-cochlear region adapted to be implanted in the cochlear, andhaving the lumen extending at least partially therethrough; and anincision region, contiguous with the intra-cochlear region, adapted tobe partially positioned in the cochlear, wherein the lumen extendingtherethrough is non-communicative across the cochleostomy.

In another aspect of invention, a prosthetic hearing implant system isdisclosed. The prosthetic hearing implant system comprises an electrodeassembly for implantation in a recipient's cochlear via a cochleostomy.The electrode assembly comprises an electrode array and an elongatecarrier member having a lumen extending longitudinally through at leasta portion thereof, and having a distal end on which the electrode arrayis disposed. The elongate carrier member comprises a distalintra-cochlear region adapted to be implanted in the cochlear, andhaving the lumen extending at least partially therethrough; and anincision region, contiguous with the intra-cochlear region, adapted tobe partially positioned in the cochlear, wherein the lumen extendingtherethrough is non-communicative across the cochleostomy.

In a further aspect of the invention, an electrode assembly forimplantation in a recipient's cochlear via a cochleostomy is disclosed.The electrode assembly comprises: an elongate stylet; an electrodearray; and an elongate carrier member having a distal end on which saidelectrode array is disposed, comprising: a distal intra-cochlear regionadapted to be implanted in the cochlear and having a lumen extending atleast partially therethrough; and an incision region, contiguous withthe intra-cochlear region, adapted to be partially positioned in thecochlear, having a non-communicative extending therethrough; and anelongate cartridge configured to slidingly receive said stylet and saidcarrier member.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described herein in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a perspective view of an implanted prosthetic hearing implantsystem having a non-communicative lumen in accordance with embodimentsof the present invention;

FIG. 2A is a side view of an electrode of assembly in accordance withone embodiment of the present invention;

FIG. 2B is a cross-sectional view of one embodiment of the of theelectrode assembly illustrated in FIG. 2A taken along section line 2B-2Bin FIG. 2A;

FIG. 2C is a cross-sectional view of one embodiment of the electrodeassembly illustrated in FIG. 2A taken along section line 2C-2C in FIG.2A;

FIG. 3A is a side view of an electrode assembly in accordance with oneembodiment of the present invention;

FIG. 3B is a cross-section view of one embodiment of the electrodeassembly shown FIG. 3A, taken along section line A-A in FIG. 3A;

FIG. 3C is a cross-section view of an alternative embodiment of theelectrode assembly shown in FIG. 3A, also taken along section line A-Ain FIG. 3A;

FIG. 4 is a side view of an electrode assembly in accordance with oneembodiment of the present invention;

FIG. 5A is a side view of an electrode assembly in accordance with oneembodiment of the present invention;

FIG. 5B is an enlarged side view of one embodiment of the electrodeassembly incision region shown in FIG. 5A;

FIG. 5B is a perspective view of one embodiment of the electrodeassembly incision region shown in FIG. 5A;

FIG. 6A is a side view of an electrode assembly in accordance with oneembodiment of the present invention;

FIG. 6B is a perspective view of the incision region of the electrodeassembly illustrated in FIG. 6A;

FIG. 6C is a cross-sectional view of the incision region of theelectrode assembly illustrated in FIGS. 6A and 6B taken along sectionline A-A in FIG. 6B;

FIG. 6D is a cross-sectional view of the incision region of theelectrode assembly illustrated in FIGS. 6A and 6B taken along sectionline B-B in FIG. 6B;

FIG. 7 is a side view of an electrode assembly in accordance with oneembodiment of the present invention;

FIG. 8A is a side view of an electrode assembly in accordance with oneembodiment of the present invention;

FIG. 8B is a cross-sectional view of the electrode assembly illustratedin FIG. 8A taken along section line 8B-8B;

FIG. 8C is a cross-sectional view of the electrode assembly illustratedin FIG. 8A taken along section line 8C-8C in FIG. 8A;

FIG. 9 is a side view of an electrode assembly in accordance with oneembodiment of the present invention;

FIG. 10 is a perspective view of an electrode assembly in accordancewith one embodiment of the present invention;

FIG. 11 is a perspective view of an electrode assembly in accordancewith one embodiment of the present invention;

FIG. 12A is a side view of an electrode assembly in accordance with oneembodiment of the present invention;

FIG. 12B is a cross-sectional view of the electrode assembly illustratedin FIG. 12A taken along section line A-A; and

FIG. 12C is a cross-sectional view of an alternative embodiment of theelectrode assembly illustrated in FIG. 12A taken along section line A-Ain FIG. 12A.

DETAILED DESCRIPTION

Aspects of the present invention are directed to an implantable elongatecarrier member, lead, catheter or the like (collectively and generallyreferred to as a “carrier member”) with an integrated lumen and atherapeutic device disposed at the distal end of the carrier member.Lumens which pass through an incision made to implant a therapeuticdevice create a potential pathway for fluids, tissue, cells, bacteria orother organic material which may, for example, damage the therapeuticdevice or cause infection, disease or other undesirable medicalconditions. For example, in the context of a cochlear implant, a carriermember lumen that extends through a cochleostomy may increase the riskof meningitis caused by fluid ingress into the lumen and, ultimately,into the cochlear.

Aspects of the present invention provide a carrier member lumen that isnon-communicative across the incision to prevent the lumen from servingas a communicative pathway for organic material through the incision. Invarious embodiments of the present invention, the non-communicativelumen is severed, removed, blocked, diverted or otherwise interrupted inthe region of the carrier which transitions through the incision therebyinterrupting the pathway for the organic material.

Exemplary embodiments of the present invention are further describedbelow in conjunction with an implanted unit of a prosthetic hearingimplant system, such as a Contour™, Freedom™, Nucleus™ or Cochlear™systems commercially available from Cochlear Limited, Australia. Suchdevices are described in U.S. Pat. Nos. 4,532,930, 6,537,200, 6,565,503,6,575,894, and 6,697,674, the entire contents and disclosures of whichare hereby incorporated by reference herein. It should be understood tothose of ordinary skill in the art that embodiments of the presentinvention may be used in other stimulating medical devices such asneurostimulators, cardiac pacemakers/defibrillators, etc.

FIG. 1 is a cut-away view of the relevant components of outer ear 101,middle ear 102 and inner ear 103, which are described next below. In afully functional ear, outer ear 101 comprises an auricle 105 and an earcanal 106. An acoustic pressure or sound wave 107 is collected byauricle 105 and channeled into and through ear canal 106. Disposedacross the distal end of ear cannel 106 is a tympanic membrane 109 whichvibrates in response to acoustic wave 107. This vibration is coupled tooval window or fenestra ovalis 110 through three bones of middle ear102, collectively referred to as the ossicles 111 and comprising themalleus 112, the incus 113 and the stapes 114. Bones 112, 113 and 114 ofmiddle ear 102 serve to filter and amplify acoustic wave 107, causingoval window 110 to articulate, or vibrate. Such vibration sets up wavesof fluid motion within cochlea 115. Such fluid motion, in turn,activates tiny hair cells (not shown) that line the inside of cochlea115. Activation of the hair cells causes appropriate nerve impulses tobe transferred through the spiral ganglion cells and auditory nerve 116to the brain (not shown), where they are perceived as sound. In deafpersons, there is an absence or destruction of the hair cells.Prosthetic hearing implant 120 is needed to directly stimulate theganglion cells to provide a hearing sensation to the recipient.

FIG. 1 also shows how an implanted prosthetic hearing implant 120 ispositioned in relation to outer ear 101, middle ear 102 and inner ear103. Prosthetic hearing implant 120 comprises external componentassembly 122 which is directly or indirectly attached to the body of therecipient, and an internal component assembly 124 which is temporarilyor permanently implanted in the recipient. External assembly 122comprises microphone 125 for detecting sound which is outputted to a BTE(Behind-The-Ear) speech processing unit 126 that generates coded signalsand are provided to an external transmitter unit 128, along with powerfrom a power source 129 such as a battery. External transmitter unit 128comprises an external coil 130 and, preferably, a magnet (not shown)secured directly or indirectly in external coil 130. Internal components124 comprise an internal receiver unit 132 having an internal coil (notshown) that receives and transmits power and coded signals from externalassembly 122 to a stimulator unit 134 to apply the coded signal along anelectrode assembly 140. Electrode assembly 140 enters cochlea 115 atcochleostomy region 142 and has one or more electrodes 150 is positionedto substantially be aligned with portions of tonotopically-mappedcochlea 115. Signals generated by stimulator unit 134 are applied by theelectrodes 150 of electrode array 144 to cochlea 115, therebystimulating the auditory nerve 116. It should be appreciated thatalthough in the embodiment shown in FIG. 1 electrodes 150 are arrangedin an array 144, other arrangements are possible.

FIGS. 2A through 2C are side and cross-sectional views, respectively, ofone embodiment of electrode assembly 140 illustrated in FIG. 1, referredto herein as electrode assembly 200. Electrode assembly 200 has anelongate carrier member 202 on which an array 144 of electrodes 150 isdisposed. Electrode assembly 200 and, hence, carrier member 202, has adistal end 210 at which electrode array 144 is disposed, and a proximalend 220 which either is connected to, or is proximate to, stimulatorunit 134 (not shown in FIG. 2A). For ease of description, futurereference to a carrier member and an electrode assembly are consideredto refer to the other unless otherwise understood from the context orexpress statements.

This illustrative embodiment of electrode assembly 200 comprises threecontiguous regions: an intra-cochlear carrier region 204 disposed towardand comprising distal end 210 of electrode assembly 200, anextra-cochlear carrier region 206 disposed toward and comprisingproximal end 220 of electrode assembly 200, and an incision region 240interposed between intra-cochlear carrier region 204 and extra-cochlearcarrier region 206.

In the exemplary cochlear implant application, the incision made toimplant an electrode assembly such as electrode assembly 140 is commonlyreferred to as a cochleostomy. For example, in the above descriptionreferring to FIG. 1, the incision in cochlear 115 is referred to ascochleostomy region 142 or, simply, cochleostomy 142. The location ofcochleostomy 142 is schematically represented in FIG. 2A by a dashedline. As one of ordinary skill in the art would appreciate, dashed line142 represents the common general location of the cochleostomy; it doesnot represent other aspects of the cochleostomy such as, for example,the thickness of the incision.

Electrode assembly 200 is configured such that, when implanted, theportion of elongate electrode assembly 200 located in cochlear 115includes intra-cochlear carrier region 204 and a portion of incisionregion 240. As such, the remaining portion of incision region 240 andextra-cochlear carrier region 206 are located external to cochlear 115when carrier member 200 is implanted.

Electrode assembly 200 further comprises a lumen 224 extending through asubstantial length of elongate carrier member 202. Lumen 224 extendsthrough a portion of extra-cochlear carrier region 206 and a portion ofintra-cochlear carrier region 204. In accordance with the teachings ofthe present invention, at least the section of incision region 240 thatextends through cochleostomy 142 is non-communicative. As such, there isno communication of organic material from the portion of the lumenexternal to cochlear 115 to the portion of the lumen internal tocochlear 115. Notably, in the embodiment shown in FIG. 2A, lumen 224 isinterrupted or absent in incision region 240, as shown in FIG. 2A. Thisis described in further detail below with reference to FIGS. 2B and 2C.FIG. 2B is a cross-sectional view of carrier member 200 taken alongsection line 2B-2B through extra-cochlear region 206 as shown in FIG.2A; FIG. 2C is a cross-sectional view of carrier member 200 taken alongsection line 2C-2C through incision region 240 as shown in FIG. 2A.

Carrier member 202 may be further considered to have an upper elongateregion 203 and a lower elongate region 205. As shown in FIGS. 2A and 2B,intra- and extra-cochlear regions 204 and 206 comprise both upper andlower elongate regions 203 and 205, while incision region 240 comprisesupper elongate region 203 and only a small portion of lower elongateregion 205. Lower elongate region 205 in incision region 240 does notinclude any portion of lumen 224. As such, the cross-sectional area ofelectrode assembly 200 in incision region 240 is less than thecross-sectional area of electrode assembly 200 in extra-cochlear region206, and lumen 224 extends through extra- and intra-cochlear regions 206and 204, and is absent in incision region 240. More generally, lumen 224in region 240 of carrier 200 extending through incision 142 isinterrupted to prevent lumen 224 from serving as a communicative pathwayfor organic material or other undesirable material through the incision.In other words, lumen 224 is a non-communicative lumen due to theabsence of lumen 224 in incision region 240.

Lumen 224 is configured to receive a straightening element 230 such as awire, which is commonly referred to as a stylet in the context ofprosthesis hearing implant systems. Regardless of application,straightening elements described herein in connection with variousembodiments of the present invention are referred to herein as styletsfor ease of reference. Prior to implanting electrode assembly 200,stylet 230 is inserted into lumen 224 to straighten electrode assembly200, which is biased to curl; that is, to have an approximately roundshape formed by one or more concentric circles. Thus, in intra-cochlearcarrier region 204, lumen 224 performs a straightening function thatholds electrode assembly 200 substantially straight during insertion.While electrode assembly 200 is inserted through cochleostomy 142, asurgeon biases forward carrier member 202 on stylet 230 to implantcarrier member 202, causing carrier member 202 to curve so as to followthe curvature of cochlear 115.

Carrier member 202 may have a series of one or more optional guide ribs208 disposed on the surface of extra-cochlear region 206 to facilitatemanual control (direct or with an instrument) of carrier member 202during implantation. In one embodiment, guide ribs 208 extend around aportion of the circumference of carrier member 200 and are raised abovesurface of carrier member 202 as shown in FIG. 2A. As one of ordinaryskill in the art would find apparent, guide ribs are not required, andwhen utilized in various embodiments of the present invention, may takeon other forms suitable for facilitating manual or instrument control ofthe carrier member.

Carrier member 202 also has a series of one or more optional markers 209disposed in or on incision region 240 of carrier member 200. In theembodiment shown in FIG. 2A, there are three markers 209 embedded in thesurface of carrier member 200. Markers 209 facilitate locating carriermember 200 such that incision region 240 is positioned so as to bepartially located within cochlear 115. As one of ordinary skill in theart would appreciate, markers 209 as well as other markers implementedin other embodiments of the present invention may be any type of devicethat facilitates visual recognition of the location of the carriermember in a recipient. Such recognition may involve imaging systems inwhich case one or more of the markers 209 will include features ormaterials identifiable by such imaging systems.

Lumen 224 in extra-cochlear carrier region 206 performs a guidingfunction rather than a straightening function since carrier member 202is straight (not pre-curved) in this region of electrode assembly 200.Such guiding function in lumen 224, and hence extra- cochlear region 206of electrode assembly 200, may provide a point to hold electrodeassembly 200 and stylet 230 well away from cochlea 115 and outside theposterior tympanotomy.

During the packing of cochleostomy area 142 with temporalis fascia, thefascia presses and hermetically seals against carrier member 202. Othertechniques to seal and hold electrode assembly 202 in cochleostomyregion 142 may be used instead of or in addition to packing, such as theuse of sutures or split bridge.

There are a number of advantages which may be derived from the aboveembodiments of the present invention. For example, electrode assembly200 may be inserted and manipulated in a manner that is substantiallysimilar to techniques commonly used to implant a conventional electrodeassembly; that is, one having a continuous lumen. Thus no new trainingis required for surgeons utilizing embodiments of the present invention.Further, the embodiments shown in FIGS. 2A through 2C may provideadditional benefits over standard electrode assemblies in that thecontacting area between carrier member 202 and stylet 230 is reduced.The reduced contact area may, in turn, reduce the dynamic frictionbetween the carrier member and stylet, thereby reducing the forcerequired to remove stylet 230 from carrier member 202. Also, thereduction in friction may decrease the propensity for stylet 230 totemporarily adhere to carrier member 202 when electrode assembly 200 isinstalled on and removed from stylet 230.

FIGS. 3A and 3B illustrate another embodiment of electrode assembly 140of the present invention, referred to herein as electrode assembly 300.FIG. 3A is a side view of electrode assembly 300 while FIG. 3B is across-section view of electrode assembly 300 taken along section lineA-A in FIG. 3A.

In the embodiment illustrated in FIGS. 3A-3B, lower elongate region 305of carrier member 302 is partially removed in incision region 340. Asshown best in FIG. 3B, the portion of lower elongate region 305 that isnot removed defines an upper surface 314 of lumen 324. That is, lumen324 is non-communicative in incision region 340 due to the partialremoval of lumen 324 in that region. It should be appreciated that thepartial removal of lumen 324 sufficient to make lumen 324non-communicative may vary depending on the particular objectives andapplications. For example, in the alternative embodiment illustrated inFIG. 3C, the remaining portion of lower elongate region 305 defines aside surface 315 of lumen 324. As such, this embodiment of lumen 324 isalso non-communicative in incision region 340 due to the partial removalof lumen 324 in that region. As one of ordinary skill in the art wouldappreciate, other portions of lower elongate region 305 of carriermember 302 may be removed or otherwise altered to make lumen 324non-communicative in incision region 340 region.

FIG. 4 is a side view of another embodiment of electrode assembly 140introduced above with reference to FIG. 1, referred to herein aselectrode assembly 400. The illustrative embodiment of electrodeassembly 400 illustrated in FIG. 4 comprises three contiguous regions:an intra-cochlear carrier region 404 disposed toward and comprisingdistal end 410 of electrode array 400, an extra-cochlear carrier region406 disposed toward and comprising proximal end 420 of electrodeassembly 400, and an incision region 440 interposed betweenintra-cochlear carrier region 404 and extra-cochlear carrier region 406.

In addition, electrode assembly 400 is formed of two integrated orunitary elongate portions: an upper elongate portion 403 and a lowerelongate portion 405. As shown in FIG. 4, lower elongate portion 405 ofcarrier member 402 is removed from extra-cochlear carrier region 404 andincision region 440. As such, lumen 424 extend through a portion ofintra-cochlear region 404 and neither cochleostomy region 142 norextra-cochlear carrier region 406. Lumen 424 has a proximal opening 416configured to receive stylet 430, as shown in FIG. 4. Thus, there is nocommunicative path through incision region 142 via lumen 424. During thepacking of cochleostomy area 142, the fascia presses and hermeticallyseals against electrode assembly 400.

It is noted that intra-cochlear carrier region 404 performs guiding andstraightening functions toward distal end 410 which allows electrodeassembly 400 to be pushed forward on stylet 430. This may improve theprecision with which electrode assembly 400 is controlled duringimplantation since the pushing of stylet 430 may occur at a locationcloser to distal end 410 of electrode assembly 400.

Since there is no carrier or lumen in cochleostomy region 142, a weakpoint may be created in electrode assembly 400. The weak point may leadto undesirable bending or kinking should electrode assembly 400 meetresistance during implantation. Therefore, in certain embodiments ofelectrode assembly 400 carrier member 402 is strengthened incochleostomy region 440.

As noted above with reference to the embodiments illustrated in FIGS.2A-2C, the contacting area between carrier member 402 and stylet 430 isreduced. This reduced contact area may, in turn, reduce the dynamicfriction between the carrier member and stylet, thereby reducing theforce required to remove stylet 430 from carrier member 402. Also asnoted above, the reduction in friction may decrease the propensity forstylet 430 to temporarily adhere to carrier member 402 when electrodeassembly 400 is installed on and removed from stylet 430.

FIGS. 5A, 5B and 5C illustrate another embodiment of an electrodeassembly 140 having a non-communicative lumen in accordance with theteachings of the present invention, referred to herein as electrodeassembly 500. FIG. 5A is a side view of electrode assembly 500.Electrode assembly 500 has a carrier member 502 formed of an upperelongate portion 503 and a lower elongate portion 505. Electrodeassembly 500 comprises three contiguous regions: an intra-cochlearcarrier region 504 disposed toward and comprising distal end 510 ofelectrode array 500, an extra-cochlear carrier region 506 disposedtoward and comprising proximal end 520 of electrode assembly 500, and anincision region 540 interposed between intra-cochlear carrier region 504and extra-cochlear carrier region 506. FIG. 5B is an enlarged side viewand FIG. 5C is a perspective view of incision carrier region 540 of FIG.5A.

Lumen 524 extends through at least a portion of intra-cochlear region504, incision region 540 and extra-cochlear carrier region 506. In FIG.5A a stylet 530 is shown partially inserted into lumen 524.

A series of one or more radial slots 550 are formed in lower elongateportion 505 of carrier member 502 in incision region 142 of electrodeassembly 500. In the embodiment shown in FIG. 5A, there are a pluralityof radial slots 550 and a plurality of radial support ribs 552. Radialslots 550 interrupt lumen 524, resulting in a lumen which isnon-communicative at a number of locations in incision region 540. Thatis, radial slots 550 ensure that there is no continuous pathway fororganic material or other undesirable elements to travel through lumen524 through cochleostomy 142.

Radial support ribs 552 provide further guiding and straighteningfunctions that assist in constraining stylet 530 during insertion andwithdrawal. Radial support ribs 552 also allow markers 209 to extend upto approximately 270° degrees around the circumference of electrodeassembly 500.

In one embodiment, radial support ribs 552 are approximately 0.2 to 1 mmin length, and radial slots 550 are approximately 0.2 mm to 1 mm inlength. In one particular embodiment, radial extensions 552 are 0.5 mmin length and radial slots 550 are 0.5 mm. In the illustrativeembodiment, radial slots 550 have similar dimensions while radialextensions 552 have similar dimensions. It should be appreciated,however, that in alternative embodiments, a different quantity of radialslots 550 have dimensions which are the same or different than thedimensions of radial extensions 552 and those illustrated in FIGS. 5A-5Cmay be implemented. It should also be appreciated that in thoseembodiments in which there is a plurality of radial slots 550 and radialsupport ribs 552, the dimensions of such radial slots and support ribsmay vary along the length of incision region 540.

FIGS. 6A through 6D illustrate another embodiment of an electrodeassembly 140 having a non-communicative lumen in accordance with theteachings of the present invention, referred to herein as electrodeassembly 600. FIG. 6A is a side view of electrode assembly 600.Electrode assembly 600 has a carrier member 602 formed of an upperelongate portion 603 and a lower elongate portion 605. Electrodeassembly 600 comprises three contiguous regions: an intra-cochlearcarrier region 604 disposed toward and comprising distal end 610 ofelectrode array 600, an extra-cochlear carrier region 606 disposedtoward and comprising proximal end 620 of electrode assembly 600, and anincision region 640 interposed between intra-cochlear carrier region 604and extra-cochlear carrier region 606. FIG. 6B is a perspective view,and FIGS. 6C and 6D are cross-sectional views taken along section linesA-A and B-B, respectively, of incision carrier region 640, as shown inFIG. 6B.

Lumen 624 extends through at least a portion of intra-cochlear region604, incision region 640 and extra-cochlear carrier region 606. A stylet630 is shown positioned within lumen 624. In incision region 640, lowerelongate region 605 comprises a series of sequentially alternatinglateral support ribs 650. That is, in one portion of incision region640, a lateral support rib 650 laterally supports stylet 630 from oneside of carrier member 602, and in a linearly adjacent portion ofincision region 640, a neighboring lateral support rib 650 laterallysupports stylet 630 from the laterally-opposing side of carrier member602.

This is illustrated in FIGS. 6C and 6D which are cross-sectional viewsof incision region 640 taken along section lines A-A and B-B in FIG. 6B.In particular, FIGS. 6C and 6D are cross-sectional views showinglinearly adjacent lateral support ribs 650 in incision region 640. Asshown in FIGS. 6B and 6C, lateral support rib 650 at section line A-Alaterally supports stylet 630 on one side of the stylet. The laterallyopposite side of lower elongate region 605 is a void 656. Conversely, asshown in FIGS. 6B and 6D, lateral support rib 650 at section line B-Blaterally supports stylet 630 on the opposing side of the stylet. Theother side of lower elongate region 605 is a void 656. Thus, stylet 630is supported in lumen 624 along incision region 640 by alternatinglateral support ribs 650. The alternating design creates a lumen 624having a non-communicative pathway in incision region 640 of electrodeassembly 600.

Lateral support ribs 650 provide further guiding and straighteningfunctions that assist in constraining stylet 630 during withdrawal.Lateral support ribs 650 also allow markers 209 to extend up toapproximately 270° degrees around the circumference of electrodeassembly 600 in incision region 640.

FIG. 7 is a side view of another embodiment of electrode assembly 140having a non-communicative lumen in accordance with the teachings of thepresent invention, referred to herein as electrode assembly 700.Electrode assembly 700 has a carrier member 702 formed of an upperelongate portion 703 and a lower elongate portion 705. Electrodeassembly 700 comprises three contiguous regions: an intra-cochlearcarrier region 704 disposed toward and comprising distal end 710 ofelectrode array 700, an extra-cochlear carrier region 706 disposedtoward and comprising proximal end 720 of electrode assembly 700, and anincision region 740 interposed between intra-cochlear carrier region 704and extra-cochlear carrier region 706.

Lumen 724 extends through at least a portion of intra-cochlear region704, incision region 740 and extra-cochlear carrier region 706. A stylet730 is shown positioned within lumen 724. The portion of lumen 724extending through intra-cochlear region 704 performs a straightening andguiding function while the portion of lumen 724 extending through extra-cochlear region 706 performs a guiding function.

A section 788 of lower elongate portion 705 of carrier member 702 inincision region 740 is removable. Upon removal of removable section 788from lower elongate portion 705, lumen 724 will be interrupted inincision region 740, resulting in a non- communicative lumen 724 acrossincision 142.

In one embodiment, removable section 788 of lower elongate portion 705is formed from a dissolvable/resorbable material. For example, incertain embodiments, removable section 788 is formed of a resorbablepolymer such as polylactic acid (PLA) and polyglycolic acid (PGA). Otherbiodegradable or dissolvable materials or combinations thereof may beused as well. After insertion of electrode assembly 700 and packing ofcochleostomy 142, the resorbable polymer is absorbed by the recipient,resulting in a non-communicative lumen 124 across incision 142.Advantageously, removable section 788 provides for a non-communicativelumen 724 in incision region 740 when electrode assembly 700 isimplanted while also enhancing the strength of electrode assembly 700during implantation.

Alternatively, section 788 is a detachable section of lower elongateportion 705 in an alternative embodiment of the present invention. Insuch alternative embodiments, section 788 is removed manually orotherwise prior to implantation or packing of cochleostomy area 142. Inone embodiment, section 788 is configured to be easily removable withforceps.

FIG. 8A is a side view of another embodiment of electrode assembly 140having a non-communicative lumen in accordance with the teachings of thepresent invention, referred to herein as electrode assembly 800.Electrode assembly 800 has a carrier member 802 formed of an upperelongate portion 803 and a lower elongate portion 805. Electrodeassembly 800 comprises three contiguous regions: an intra-cochlearcarrier region 804 disposed toward and comprising distal end 810 ofelectrode array 800, an extra-cochlear carrier region 806 disposedtoward and comprising proximal end 820 of electrode assembly 800, and anincision region 840 interposed between intra-cochlear carrier region 804and extra-cochlear carrier region 806.

Lumen 824 extends through at least a portion of intra-cochlear region804, incision region 840 and extra-cochlear carrier region 806. In thisembodiment, lumen 824 is a collapsible lumen that expands in response toan insertion force applied to stylet 830. FIG. 8A is a cross-sectionalview of carrier member 802 taken along section line 8B-8B of FIG. 8A. Asshown in FIGS. 8A and 8B, collapsible lumen 824 is forced open andextends around the circumference of the inserted portion of stylet 830.

FIG. 8C is a cross-sectional view of carrier member 802 taken alongsection line 8C-8C of FIG. 8A. As shown in FIG. 8A, stylet 830 does notextend through lumen 824 to section line 8C-8C. As such, lumen 824 iscollapsed at section line 8C-8C, as shown in FIG. 8C. Thus, lumen 824expands and collapses in response to the introduction and presence ofstylet 830. Prior to implantation, stylet 830 is inserted into collapsedlumen 824, causing lumen 824 to expand around stylet 830. Then,electrode assembly 800 is implanted during which stylet 830 is removedfrom lumen 824. As stylet 830 is removed, lumen 824 collapses onceagain, resulting in a non-communicative lumen. In such embodiments,lumen 824 is non-communicative along its entire length as compared tocertain other embodiments of the present invention in which lumen 824 isnon-communicative only in incision region 142.

In addition, packing lumen 824 will further compress and creates a sealand a non-communicative path in lumen 824. During the packing ofcochleostomy 142, the fascia presses and hermetically seals againstelectrode assembly 800. Lumen 824 may also be plugged with a pluggingmaterial (not shown) once stylet 830 is fully removed. As one ofordinary skill in the art would appreciate, in such embodiments carriermember 802 performs guiding and straightening functions throughout itsentire length.

FIG. 9 is a side view of another embodiment of electrode assembly 140having a non-communicative lumen in accordance with the teachings of thepresent invention, referred to herein as electrode assembly 900.Electrode assembly 900 has a carrier member 902 formed of an upperelongate portion 903 and a lower elongate portion 905. Electrodeassembly 900 comprises three contiguous regions: an intra-cochlearcarrier region 904 disposed toward and comprising distal end 910 ofelectrode array 900, an extra-cochlear carrier region 906 disposedtoward and comprising proximal end 920 of electrode assembly 900, and anincision region 940 interposed between intra-cochlear carrier region 904and extra-cochlear carrier region 906.

Lumen 924 extends through at least a portion of intra-cochlear region904, incision region 940 and extra-cochlear carrier region 906. In thisembodiment, lumen 924 is interrupted along two sections 950A and 950B inincision region 940. Section 950A and 950B are divided by a support rib952. In the illustrative embodiment, such interruption is attained bythe absence of lower elongate portion 905 of carrier member 902.Advantageously, this allows electrode assembly 900 to be positioned atdifferent depths to account for the various depth requirements ofelectrode assembly 900.

FIGS. 10 and 11 are perspective views of two embodiments of an electrodeassembly 140 having a non-communicative lumen in accordance with theteachings of the present invention, referred to herein as electrodeassembly 1000 and 1100, respectively. Electrode assemblies 1000 and 1100each comprises three contiguous regions similar to those described abovein connection with other embodiments of the present invention. In FIGS.10 and 11 only a portion of incision region 1040 and 1140, respectively,are shown for clarity.

Electrode assembly 1000 has a carrier member 1002 formed of an upperelongate portion 1003 and a lower elongate portion 1005. Similarly,electrode assembly 1100 has a carrier member 1102 formed of an upperelongate portion 1103 and a lower elongate portion 1105.

Carrier members 1002 and 1102 each have a raised surface 1007 and 1107,respectively, formed on upper elongate portion 1003 and 1 103, inincision region 1004 and 1104, respectively. Raised surfaces 1007 and1107 are provided in addition or alternatively to markers 209 describedabove in connection with other embodiments of the present invention. Aremovable cartridge 1080 and 1180 travels parallel with the longitudinalaxis of the respective carrier members 1002 and 1102 on rails 1070, 1170formed in the upper elongate portions 1005, 1105, respectively.

In both embodiments, stylets 1030, 1130 extend through the respectivelumen 1024, 1124 that is provided in extra-cochlear region (not shown)and intra-cochlear region 1004, 1104, respectively. In incision regions1040 and 1140, lower elongate portions 1005 and 1105 are at leastpartially absent to provide a non-communicative lumen in incisionregions 1040 and 1140. In the embodiment shown in FIG. 10, lowerelongate portion 1005 is completely absent while in the embodiment shownin FIG. 11, lower elongate portion 1105 is partially absent.

In both embodiments, upper elongate portions 1005 and 1105 form a railadapted to be slidingly received by slots 1082 and 1182, respectively,of their respective cartridge 1080 and 1180. Removal cartridges 1080 and1180 may slide or fit over rails 1070 and 1170 as shown in FIGS. 10 and11. Further, removal cartridges 1080 and 1180 may be connected to therespective stylet 1030 and 1130 to enable the surgeon to guide thestylet out of the respective lumen 1024 and 1124. Removal cartridges1080 and 1180 may enhance the strength of electrode assemblies 1000 and1100 and provide straightening and guiding functions.

It should be appreciated that the rails in the above embodiments areoptional and that cartridges may be part of the insertion tool. Anexample of such an embodiment is illustrated in FIGS. 12A and 12B. FIGS.12A and 12B are side and cross-sectional views, respectively, of oneembodiment of electrode assembly 140 illustrated in FIG. 1, referred toherein as electrode assembly 1200. Electrode assembly 1200 has anelongate carrier member 1202 on which an array 144 of electrodes 150 isdisposed. Electrode assembly 1200 and, hence, carrier member 1202, has adistal end 1210 at which electrode array 144 is disposed, and a proximalend 1220 which either is connected to, or is proximate to, stimulatorunit 134 (not shown in FIGS. 12A and 12B).

This illustrative embodiment of electrode assembly 1200 comprises threecontiguous regions: an intra-cochlear carrier region 1204 disposedtoward and comprising distal end 1210 of electrode assembly 1200, anextra-cochlear carrier region 1206 disposed toward and comprisingproximal end 1220 of electrode assembly 1200, and an incision region1240 interposed between intra-cochlear carrier region 1204 andextra-cochlear carrier region 1206.

Carrier member 1202 is formed of an upper elongate portion 1203 and alower elongate portion 1205. A removable cartridge 1280 travels parallelwith the longitudinal axis of carrier members 1202. Cartridge 1280 isconfigured to slidingly receive carrier member 1202 and stylet 1230. Assuch, carrier member 1202 has a lumen 1224 in intra-cochlear region1204. Rather, stylet 1230 extends through cartridge 1280 inextra-cochlear region 1206 (not shown) and incision region 1240, andextends through lumen 1205 in intra-cochlear region 1204. In incisionregion 1240 lower elongate portion 1205 is at least partially absent toprovide a non-communicative lumen in incision region 1240, although anyof the above or other embodiments of the present invention may beimplemented to provide a non-communicative lumen in incision region1240. Removal cartridges 1280 may be connected to stylet 1230 to enablethe surgeon to guide the stylet out of lumen 1224 by removing cartridge1280.

In the above exemplary embodiments, the carrier member has beendescribed as comprising an upper elongate portion and a lower elongateportion with the lumen extending through the lower elongate portion ofone or more contiguous regions of the electrode assemblies. As one ofordinary skill in the art should find apparent, this distinction betweenupper elongate portion and lower elongate portion is arbitrary andpresented for ease of description only. For example, the upper and lowerelongate portions of the carrier member may be part of an integrated orunitary carrier member. Furthermore, there is no restriction with regardas to where in the carrier member the lumen is located. For example, thelumen may extend through the lower elongate portion, the upper elongateportion, or some combination thereof.

Although the present invention has been fully described in conjunctionwith several embodiments thereof with reference to the accompanyingdrawings, it is to be understood that various changes and modificationsmay be apparent to those skilled in the art. For example, it should beunderstood, that any of the above-described embodiments of the presentinvention may be combined in any way feasible to attain anon-communicative lumen of the present invention. As another example,the foregoing embodiments of the present invention may also have adistal opening in the intra-cochlear lumen or portion of the lumen thatextends into the cochlea. This may create an open lumen at the tip. Anopen lumen would not increase the potential for an transport of organicmaterial across the cochleostomy since the lumen is sealed at incisionregion 142. Further, the foregoing exemplary embodiments may also be acombination of plugs at any different openings in the lumen to furtherconvert portions of the lumen to non-communicative pathways. As anotherexample, embodiments of the present invention utilize carrier membersmade of silicone, polymers and/or other biocompatible materials suitablefor implantation and which may be configured to attach to electrodeassemblies. Also, further applications of stylet insertion devices andcarriers are described in the U.S. Pat. No. 6,421,569 and US PatentPublished Application Nos. 2004/0236390, 2004/0172118, 2004/0122501,2004/0030376, 2003/0181967, 2003/0171758, 2003/0093139, 2003/0045921,and 2002/0029074, the entire contents and disclosures of which arehereby incorporated by reference herein. Such changes and modificationsare to be understood as included within the scope of the presentinvention as defined by the appended claims, unless they departtherefrom.

All documents, patents, journal articles and other materials cited inthe present application are hereby incorporated by reference.

1. An electrode assembly for implantation in a recipient's cochlear viaa cochleostomy, comprising: an electrode array; and an elongate carriermember having a lumen extending longitudinally through at least aportion thereof, and having a distal end on which said electrode arrayis disposed, comprising: a distal intra-cochlear region adapted to beimplanted in the cochlear and having the lumen extending at leastpartially therethrough; and an incision region, contiguous with theintra-cochlear region, adapted to be partially positioned in thecochlear, wherein the lumen extending therethrough is non-communicativeacross the cochleostomy.
 2. The electrode assembly of claim 1, whereinthe carrier member further comprises: a proximal extra-cochlear region,contiguous with the incision region, adapted to be positioned externalthe cochleostomy.
 3. The electrode assembly of claim 2, wherein theproximal extra-cochlear region is configured such that the lumen extendsat least partially through the extra-cochlear region.
 4. The electrodeassembly of claim 1, wherein at least a portion of the carrier member inthe incision region is removed so as to form an aperture in the lumenextending therethrough.
 5. The electrode assembly of claim 1, whereinthe lumen is one of either severed, removed, blocked, diverted orinterrupted in the region of the carrier which is to be proximate thecochleostomy.
 6. The electrode assembly of claim 1, wherein the lumen isconfigured to receive a stylet.
 7. The electrode assembly of claim 1,wherein the portion of the carrier member through which the lumenextends in the incision region is absent.
 8. The electrode assembly ofclaim 1, wherein the portion of the carrier member that is present inthe incision region defines an upper surface of lumen.
 9. The electrodeassembly of claim 1, wherein the portion of the carrier member that ispresent in the incision region defines side upper surface of lumen. 10.The electrode assembly of claim 1, wherein the portion of the carriermember that is present in the incision region comprises a plurality ofradial slots resulting in a plurality of spaced radial support ribs. 11.The electrode assembly of claim 10, wherein the radial support ribs andthe radial slots have substantially the same length.
 12. The electrodeassembly of claim 10, wherein the radial support ribs are approximately0.2 to 1.0 mm in length, and wherein the radial slots are approximately0.2 mm to 1.0 mm in length
 13. The electrode assembly of claim 10,wherein the radial support ribs are approximately 0.2 to 1.0 mm inlength, and wherein the radial slots are approximately 0.2 mm to 1.0 mmin length
 14. The electrode assembly of claim 1, wherein the portion ofthe carrier member that is present in the incision region comprises aplurality of lateral support ribs collectively supporting a styletinstalled in the lumen.
 15. The electrode assembly of claim 14, whereinthe plurality of lateral support ribs alternate longitudinally along theincision region.
 16. The electrode assembly of claim 1, wherein asection of the incision region of the carrier member that forms acircumference of at least a portion of the lumen is removable from thecarrier member, wherein when the removable section is removed, the lumenis non-communicative.
 17. The electrode assembly of claim 16, whereinthe removable section of the carrier member is formed from adissolvable/resorbable material.
 18. The electrode assembly of claim 17,wherein the dissolvable/resorbable material comprises one or more of thegroup consisting of polylactic acid (PLA) and polyglycolic acid (PGA).19. The electrode assembly of claim 16, wherein the removable section ofthe carrier member is a manually-detachable section of the carriermember.
 20. The electrode assembly of claim 1, wherein the carriermember further comprises: a raised surface integral with the incisionregion of the carrier member.
 21. The electrode assembly of claim 1,wherein the carrier member is constructed so as to be resistant tobending in the incision region.
 22. The electrode assembly of claim 1,wherein the lumen is configured to expand and contract in response toforced insertion and removal, respectively, of a stylet, wherein whenthe lumen is collapsed the lumen is non-communicative.
 23. The electrodeassembly of claim 1, wherein the carrier member further comprises araised surface formed on the incision region wherein a rail is formed ata juncture of the raised surface and the carrier member, and wherein theelectrode assembly further comprises: a removable cartridge coupled tothe stylet and configured to travel on the rail parallel with alongitudinal axis of the carrier member.
 24. A prosthetic hearingimplant system comprising: an electrode assembly for implantation in arecipient's cochlear via a cochleostomy, comprising an electrode arrayand an elongate carrier member having a lumen extending longitudinallythrough at least a portion thereof, and having a distal end on which theelectrode array is disposed, the elongate carrier member comprising: adistal intra-cochlear region adapted to be implanted in the cochlear,and having the lumen extending at least partially therethrough; and anincision region, contiguous with the intra-cochlear region, adapted tobe partially positioned in the cochlear, wherein the lumen extendingtherethrough is non-communicative across the cochleostomy.
 25. Thesystem of claim 24, wherein the carrier member further comprises: aproximal extra-cochlear region, contiguous with the incision region,adapted to be positioned external the cochleostomy.
 26. The system ofclaim 24, wherein the proximal extra-cochlear region is configured suchthat the lumen extends at least partially through the extra-cochlearregion.
 27. The system of claim 24, wherein at least a portion of thecarrier member in the incision region is removed so as to form anaperture in the lumen extending therethrough.
 28. The system of claim24, wherein the lumen is one of either severed, removed, blocked,diverted or interrupted in the region of the carrier which is to beproximate the cochleostomy.
 29. The system of claim 24, wherein thelumen is configured to receive a stylet.
 30. The system of claim 24,wherein the portion of the carrier member through which the lumenextends in the incision region is absent.
 31. The system of claim 24,wherein the portion of the carrier member that is present in theincision region defines an upper surface of lumen.
 32. The system ofclaim 24, wherein the portion of the carrier member that is present inthe incision region defines side upper surface of lumen.
 33. The systemof claim 24, wherein the portion of the carrier member that is presentin the incision region comprises a plurality of radial slots resultingin a plurality of spaced radial support ribs.
 34. The system of claim33, wherein the radial support ribs and the radial slots havesubstantially the same length.
 35. The system of claim 25, wherein theportion of the carrier member that is present in the incision regioncomprises a plurality of lateral support ribs collectively supporting astylet installed in the lumen.
 36. The system of claim 35, wherein theplurality of lateral support ribs alternate longitudinally along theincision region.
 37. The system of claim 24, wherein a section of theincision region of the carrier member that forms a circumference of atleast a portion of the lumen is removable from the carrier member,wherein when the removable section is removed the lumen becomesnon-communicative.
 38. The system of claim 37, wherein the removablesection of the carrier member is formed from a dissolvable/resorbablematerial.
 39. The system of claim 38, wherein the dissolvable/resorbablematerial comprises polylactic acid (PLA).
 40. The system of claim 38,wherein the dissolvable/resorbable material comprises polyglycolic acid(PGA).
 41. The system of claim 37, wherein the removable section of thecarrier member is a manually-detachable section of the carrier member.42. The system of claim 41, wherein the manually-detachable section ofthe carrier member is configured to be removable with surgical forceps.43. The system of claim 24, wherein the lumen is configured to expandand contract in response to forced insertion and removal, respectively,of a stylet, wherein when the lumen is collapsed the lumen isnon-communicative.
 44. The system of claim 24, wherein the carriermember further comprises a raised surface formed on the incision regionwherein a rail is formed at a juncture of the raised surface and thecarrier member, and wherein the electrode assembly further comprises: aremovable cartridge coupled to the stylet and configured to travel onthe rail parallel with a longitudinal axis of the carrier member.
 45. Anelectrode assembly for implantation in a recipient's cochlear via acochleostomy, comprising: an elongate stylet; an electrode array; and anelongate carrier member having a distal end on which said electrodearray is disposed, comprising: a distal intra-cochlear region adapted tobe implanted in the cochlear and having a lumen extending at leastpartially therethrough; and an incision region, contiguous with theintra-cochlear region, adapted to be partially positioned in thecochlear, having a non-communicative extending therethrough; and anelongate cartridge configured to slidingly receive said stylet and saidcarrier member.
 46. The electrode assembly of claim 45, wherein thecarrier member further comprises: a proximal extra-cochlear region,contiguous with the incision region, adapted to be positioned externalthe cochleostomy.
 47. The electrode assembly of claim 45, wherein thelumen is one of either severed, removed, blocked, diverted orinterrupted in the region of the carrier which is to be proximate thecochleostomy.